HEINZ has been criticised by
environmentalists after admitting lining its food cans with a chemical thought
to mimic female hormones, writes Jonathan Leake.

In animal experiments
researchers have found that the chemical, bisphenol A, can cause early puberty
in females and may reduce the growth of reproductive tissues in young males.

"This chemical is a known endocrine disruptor and is found in a range of
other common domestic products besides Heinz's tins," said Dr Michael Warhurst
who is leading a Friends of the Earth campaign to highlight the issue. "It is
one of many chemicals to which we are constantly exposed and which are increasingly
linked with various illnesses."

Heinz confirmed that it uses very
small amounts of bisphenol A to line the lids of cans fitted with ring-pull openers,
including baked bean cans. The chemical helps to prevent such tins from corroding
or releasing tin into the food.

Bisphenol A and most other endocrine
disrupting chemicals are known toxins at high levels. The argument is about whether
or not they are dangerous in very low levels, when they are known as micropollutants.

Heinz says it accepts that tiny amounts of bisphenol A may leach into
its foods, but says levels are far below what is needed to cause any biological
effect. "The levels are in parts per million or parts per billion, so small as
to be almost undetectable," said a spokesman.

Tin cans are just one
of many potential sources of bisphenol A. The metal is also used in soft plastics,
pesticides, dental products and some baby bottles.

A 1999 study by
American researchers found that bisphenol A could mimic the sex hormone estradiol.
Mice exposed before birth to the chemical, in amounts correlating with typical
human exposures, suffered changes in postnatal growth and early puberty in females.